Botox (onabotulinumtoxinA) for the treatment of migraine headaches prevention: an introduction

Botox received FDA approval for the treatment of chronic migraine in October 2010.

Botox is an injectable form of botulinum toxin called onabotulinumtoxin A. It is used for preventing migraines in adults with chronic migraine (migraines that occur at least 15 days per month with a headache lasting at least 4 hours per day).

How Botox for migraines works

Botox works by blocking the release of certain brain chemicals including acetylcholine and by blocking the movement of certain nerves and muscles. It is not completely known how Botox reduces headache pain and stiffness. A potential reason might be that Botox blocks nerves that send pain messages to the brain and relaxes muscles so they are less sensitive to pain.  More detailed information on Botox can be found at drugfx.com.

Botox’s effectiveness

Patients have differing levels of success with each type of treatment. Some feel reasonably better quickly, while others find their migraine symptoms completely go way.   Botox was evaluated in 2 well designed studies that included people who were not using migraine prevention medicines but who were experiencing more than 15 days of probable migraine headache per month lasting at least 4 hours per day. Results included measurable and meaningful differences after 24 weeks as compared to people who received sugar injections including:

• Number of headache days per 28 days : patients receiving Botox had approximately 2.3 fewer headache days compared to the placebo group (7.8 to 9.2 fewer days for the Botox group, versus 6.4 to 6.9 days for the placebo group, respectively)
• Patients receiving Botox also experienced a reduction in total headache hours compared to the placebo group.

Forms of Botox available to treat migraines

Botox is available in injectable form. Botox and Botox Cosmetic (the form of Botox given for reducing facial wrinkles) both contain the same ingredients but have different approved uses and labeling. When given for chronic migraine, Botox is diluted and a series of 31 injections are given across 7 specific regions on both the left and right sides of the head and neck. It is recommended that this treatment be repeated every 12 weeks.

Approximate Cost of Botox for migraine

The cost of a 100 unit vial of Botox is approximately $525.

Note that a typical dose of Botox for migraine treatment is 155 units.

Most common side effects of Botox injection

In general, Botox treatment was well tolerated by the large majority of patients and few people in the studies stopped participating because of side effects (4% in the Botox treated group and 1% in the placebo group). In both studies, side effects that were reported by more than 2% of people treated with Botox and more frequent than in patients treated with placebo included:

• Headache
• Facial loss of movement
• Eyelid drooping
• Lung inflammation
• Neck pain
• Muscle stiffness and weakness
• Muscle pain and spasms
• Pain at injection site
• High blood pressure

More detailed information on Botox side effects can be found at drugfx.com.

Serious side effects

In rare circumstances, the paralyzing effect of Botox can spread to other areas of the body and can cause general weakness, double vision, difficulty swallowing, voice and speech disorders, loss of bladder control and difficulty breathing. The spread of effect beyond the areas treated for approved uses at approved doses have not generally been reported.

Who should not take Botox for migraines

Botox is not for every patient. People should avoid Botox if they are allergic to any of the ingredients, have had an allergic reaction to other similar products or have a skin infection at the site where Botox will be injected. Caution should be exercised for people who have any disease that affects their muscles or nerves, those with breathing, swallowing or bleeding problems as well as those who have facial weakness such as drooping eyelids or recent facial surgery. It is not know whether  it is safe to be pregnant or breast feed while using Botox.

As always, the best source for advice on treating your migraines is your own migraine specialist. These medication descriptions are provided only for informational purposes. You should begin no medication regimen without first checking with your physician. Again, this information should in no way substitute or be mistaken for medical advice.

Written by: Otesa Miles / Reviewed by: John-Claude Krusz, PhD, MD | Last review date: November 2010. Click the References Link below for a complete list of references.

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